Liquid storage unit

A liquid storage unit comprising:

• a case in which an opening is provided on one of rectangular parallelepiped maximum area surfaces;
• and
• a liquid storage pack that includes a flat bag body for storing a liquid and a rectangular parallelepiped adapter, and that is detachably mounted on an inside of the case through the opening, the adapter being attached to one end of the bag body and provided with a supply port of the liquid, wherein
• assuming that a direction connecting the opening of the case and a bottom surface facing the opening is a first direction,
• the adapter includes concave portions provided so as to extend in the first direction on opposite outer side surfaces, respectively, the outer side surface being a side surface continuous with a surface on which the supply port is provided, and not facing the bottom surface of the case,
• the case includes convex portions that complementarily fit to the concave portions on inner side surfaces of the case facing the outer side surfaces of the adapter on which the concave portions are provided, in a state in which the liquid storage pack is mounted, and
• an outer side surface region including the concave portion of the adapter and a side surface region including the convex portion of the case each have a structure in which one region and the other region are asymmetric with respect to a surface perpendicular to the first direction.